Method and apparatus for selectively configuring a two-way radio device to operate in a control station mode or a non-control station mode

Abstract

A method and apparatus for operating a two-way radio device includes a receiver front end that has a low noise amplifier (LNA) and an adjustable attenuator coupled to the output of the LNA. The bias provided to the LNA is adjustable in correspondence with a mode selection of either a control station mode or a non-control station mode of operating the two-way radio device. Since changing the bias level of the LNA changes the gain of the LNA, the adjustable attenuator can be adjusted accordingly to maintain a desired gain level for subsequent portions of the receiver front end.

We claim: 
     
         1 . A receiver front end for a two-way radio device, comprising:
 a low noise amplifier that amplifies signals received via an antenna;   a bias adjustment network that adjusts a bias of the low noise amplifier responsive to a bias control signal;   an adjustable attenuator coupled in series with the low noise amplifier that selectively attenuates an output of the low noise amplifier responsive to an attenuation control signal; and   a controller that asserts the bias control signal and the attenuation control signal when the two-way radio device is operated in a control station mode, wherein asserting the bias control signal causes the bias adjustment network to increase bias to the low noise amplifier, and asserting the attenuator control signal causes the adjustable attenuator to increase an attenuation of the output of the low noise amplifier.   
     
     
         2 . The receiver front end of  claim 1 , wherein the bias control signal and the attenuator control signal are not asserted when the two-way radio device is not operated in the control station mode. 
     
     
         3 . The receiver front end of  claim 1 , wherein the attenuator control signal is further controlled by an automatic gain control stage of the controller, and the adjustable attenuator is adjusted via the attenuator control signal to achieve a desired signal gain from the output of the low noise amplifier. 
     
     
         4 . The receiver front end of  claim 1 , wherein the adjustable attenuator provides an attenuated output of the low noise amplifier, and wherein the attenuated output is provided to a demodulator of the two-way radio device. 
     
     
         5 . The receiver front end of  claim 1 , wherein the bias adjustment network increases a linearity of the low noise amplifier when the bias control signal is asserted by the controller. 
     
     
         6 . The receiver front end of  claim 1 , wherein the receiver front end is a direct conversion receiver front end. 
     
     
         7 . The receiver front end of  claim 1 , wherein the controller asserts the bias control signal and attenuation control signal responsive to a user input selecting the control station mode via a user interface of the two-way radio device. 
     
     
         8 . The receiver front end of  claim 1 , wherein the controller asserts the bias control signal and attenuation control signal responsive to a control station accessory being connected to the two-way radio device. 
     
     
         9 . The receiver front end of  claim 1 , wherein the bias control signal is controlled by an automatic gain control stage of the controller, and the bias adjustment network is adjusted via the bias control signal to achieve a desired signal gain of the low noise amplifier. 
     
     
         10 . The receiver front end  claim 1 , wherein the bias control signal and the attenuator control signal are common. 
     
     
         11 . A method of operating a receiver front end for a two-way radio device, comprising:
 determining a mode of operation of the two-way radio device, wherein the mode of operation is a control station mode or a non-control station mode;   when the determined mode of operation is the non-control station mode, adjusting a bias level of a low noise amplifier to a first bias level, and adjusting an adjustable attenuator coupled to an output of the low noise amplifier to a first attenuation level;   when the determined mode of operation is the control station mode, adjusting a bias level of the low noise amplifier to a second bias level, and adjusting the adjustable attenuator to a second attenuation level; and   wherein the first bias level is lower than the second bias level and the first attenuation level is a lower attenuation than the second attenuation level.   
     
     
         12 . The method of  claim 11 , wherein determining the mode of operation comprises determining a default mode upon powering up the two-way radio device. 
     
     
         13 . The method of  claim 11 , wherein determining the mode of operation comprises receiving a user input at the two-way radio device that indicates a user selectable choice between the control station mode and the non-control station mode. 
     
     
         14 . The method of  claim 11 , wherein determining the mode of operation comprises determining either the connection or disconnection of an accessory associated with the control station mode. 
     
     
         15 . The method of  claim 11 , wherein adjusting the adjustable attenuator to the first attenuation level comprises adjusting the adjustable attenuator to zero attenuation. 
     
     
         16 . The method of  claim 11 , wherein adjusting the bias level of the low noise amplifier to the second bias level causes the low noise amplifier to have a small signal gain of substantially 3 dB over the small signal gain of the low noise amplifier when the low noise amplifier is operated at the first bias level. 
     
     
         17 . The method of  claim 11 , wherein adjusting the bias level of the low noise amplifier and adjusting the attenuation level of the adjustable attenuator are performed using a common control signal provided to both the low noise amplifier and the adjustable attenuator. 
     
     
         18 . The method of  claim 11 , wherein adjusting the bias level of the low noise amplifier and adjusting the adjustable attenuator are performed independently of each other by a bias control signal provided to the low noise amplifier and an attenuation control signal provided to the adjustable attenuator. 
     
     
         19 . A two-way radio device operable in either a control station mode or a non-control station mode, comprising:
 a processor;   at least one user interface element coupled to the processor that indicates a desired mode of operation of the two-way radio device to the processor;   a receiver front end having a low noise amplifier (LNA) and an adjustable attenuator coupled to an output of the LNA, a bias adjustment network that adjusts a bias of the low noise amplifier responsive to a bias control signal, and a controller that asserts the bias control signal and the attenuation control signal when the two-way radio device is operated in a control station mode, wherein asserting the bias control signal causes the bias adjustment network to increase bias to the low noise amplifier, and asserting the attenuator control signal causes the adjustable attenuator to increase an attenuation of the output of the low noise amplifier, and wherein the controller is responsive to the processor indicating the desired mode of operation to be either the control station mode or the non-control station mode.   
     
     
         20 . The two-way radio device of  claim 19 , wherein the bias level provided to the LNA in the control station mode causes the LNA to have a small signal gain of substantially 3 dB above the small signal gain of the LNA when the LNA is biased to operate in the non-control station mode.